Method of and apparatus for detecting faults in the operation of open-end spinning machines

Abstract

Faults in produced yarn occurring by fouling of spinning units can be detected by measuring changes in the cross-sectional diameter of the yarn and producing a control signal indicating irregularities. The apparatus of this invention includes a measuring device for measuring the cross-sectional diameter and producing a signal representative thereof, which signal is processed in a discriminator circuit, including at least a correcting circuit with a non-linear characteristic, an integrating circuit and a comparison circuit to compare the integrated signal with a predetermined standard, thereby producing the control signal.

I claim: 
     
       1. A method of detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, which method comprises the steps of measuring the cross-section or diameter of yarn leaving at least one spinning unit,   converting the measurement into an electrical signal, and   processing said electrical signal in a discriminator to detect irregularities in said measurement by   applying a non-linear correcting characteristic to said signal,   integrating the corrected signal in an integrator, and   comparing the integrated signal with a predetermined reference signal in a comparator,   thereby generating a control signal upon the occurrence of said irregularities,   wherein said predetermined reference signal is formed from the average value of the output signals of at least two of said integrators, each of which is associated with a different spinning unit.   
     
     
       2. A method of detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, which method comprises the steps of measuring the cross-section or diameter of yarn leaving at least one spinning unit,   converting the measurement into an electrical signal, and   processing said electrical signal in a discriminator to detect irregularities in said measurement by   applying a non-linear correcting characteristic to said signal by a correcting means,   integrating the corrected signal in an integrator, and   comparing the integrated signal with a predetermined reference signal in a comparator,   thereby generating a control signal upon the occurrence of said irregularities,   wherein periodically recurring changes in yarn cross-section are detected by frequency-selective filters as irregularities in said electrical signal, and   wherein said electrical signal having said irregularities is applied to the input of the correcting means by parallel connection of high-pass and low-pass frequency-selective filters to said correcting means to select only frequencies above the cut-off of said high-pass filter and below the cut-off of said low-pass filter, and suppress all frequencies therebetween.   
     
     
       3. A method as claimed in claim 2, wherein irregularities of different kinds are present as separate components of said electrical signal, the separate components being further processed with different emphasis. 
     
     
       4. An apparatus for detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, said apparatus comprising measuring means for generating an electrical signal representative of the cross-sectional diameter of yarn passing from at least one spinning unit, and   discrimator means connected to said measuring means for generating a control signal in response to irregularities in said electrical signal, said irregularities being representative of excessive variations in said cross-sectional diameter,   wherein said discriminator means includes at least one correcting circuit means with a non-linear characteristic for applying said non-linear characteristic to said electrical signal,   an integrator circuit means connected to said correcting circuit means for integrating the corrected signal, and   a comparison circuit means connected to said integrator circuit means for comparing the integrated signal with a predetermined reference signal,     wherein said discriminator means further includes at least one frequency-selective filter means for determining frequency components of said electrical signal, and   wherein said frequency-selective filter means include high-pass and low-pass frequency-selective filters connected in parallel to said correcting circuit means to select only frequencies above the cut-off of said high-pass filter and below the cut-off of said low-pass filter, and suppress all frequencies therebetween.     
     
     
       5. An apparatus as claimed in claim 4, wherein components of the input signal applied to sid integrator circuit means are individually adjustable or weighted, said components being formed by said correcting circuit means and said frequency-selective filter means. 
     
     
       6. An arrangement for detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, said apparatus comprising measuring means for generating an electrical signal representative of the cross-sectional diameter of yarn passing from at least one spinning unit, and   discriminator means connected to said measuring means for generating a control signal in response to irregularities in said electrical signal, said irregularities of excessive variations in said cross-sectional diameter,   wherein sid discriminator means includes at least one correcting circuit means with a non-linear characteristic for applying said non-linear characteristic to said electrical signal,   an integrator circuit means connected to said correcting circuit means for integrating the corrected signal, and   a comparison circuit means connected to said integrator circuit means for comparing the integrated signal with a predetermined reference signal, and   wherein said predetermined reference signal is provided by the outputs of at least two of said integrator circuit means connected in parallel.     
     
     
       7. A method of detecting the defective operation of spinning units in open-end spinning machines comprising the steps of measuring the cross-section or diameter of yarn leaving at least one spinning unit,   converting the measurement into an electrical signal, and   processing said electrical signal in a discriminator to detect irregularities in said measurement by applying a non-linear characteristic to said electrical signal with a correcting device receiving said electrical signal to provide a corrected signal which emphasizes larger deviations of said cross-section or diameter of said yarn over smaller deviations thereof,   integrating said corrected signal in an integrator connected to said correcting device to determine the frequency of occurrence of said larger deviations of said yarn, and   comparing the integrated signal with a predetermined reference signal in a comparator connected to said integrator,   thereby generating a control signal upon the occurrence of predetermined deviations of said cross-section or diamter of said yarn.     
     
     
       8. A method as claimed in claim 7, wherein said non-linear characteristic is adjustable. 
     
     
       9. A method as claimed in claim 7, wherein said predetermined reference signal is adjustable. 
     
     
       10. A method as claimed in claim 9, wherein said predetermined reference signal is simultaneously adjusted for at least two spinning units. 
     
     
       11. A method as claimed in claim 7, wherein said predetermined reference signal is formed from the average value of the output signals of at least two of said integrators, each of which is associated with a different spinning unit. 
     
     
       12. A method as claimed in claim 7, wherein said electrical signal is obtained as an analogue value, converted into a digital signal in an analogue-digital converter receiving said electrical signal and connected to the input of said correcting device, and processed as a digital signal in said correcting device, said integrator and said comparator. 
     
     
       13. A method as claimed in claim 7, wherein periodically recurring changes in yarn cross-section are detected by frequency-selective filters as irregularities in said electrical signal. 
     
     
       14. A method as claimed in claim 13, wherein said electrical signal having said irregularities is applied to the input of said correcting device with a series connection of said frequency-selective filters. 
     
     
       15. A method as claimed in claim 14, wherein irregularities of different kinds are present as separate components of said electrical signal, the separate components being further processed with different emphasis, said different emphasis being selected by the choise of said frequency-selective filters. 
     
     
       16. A method as claimed in claim 13, wherein said electrical signal having said irregularities is applied to the input of said correcting device by parallel connection of high-pass and low-pass frequency-selective filters to said correcting device to select only frequencies above the cut-off of said high-pass filter and below the cut-off of said low-pass filter, and suppress all frequencies therebetween. 
     
     
       17. A method as claimed in claim 16, wherein irregularities of different kinds are present as separate components of said electrical signal, the separate components being further processed with different emphasis. 
     
     
       18. A method as claimed in claim 7, wherein said electrical signal provides a second control signal for monitoring yarn travel, the spinning unit being swtiched off in the absence of said additional control signal. 
     
     
       19. A method as claimed in claim 7, wherein said electrical signal and the processed signals are applied to a central data-processing facility for further evaluation of the operation of the spinning unit. 
     
     
       20. An apparatus for detecting the defective operation of spinning units in open-end spinning machines comprising measuring means for generating an electrical signal representative of the cross-section or diameter of yarn passing from at least one spinning unit, and   discriminator means connected to said measuring means for generating a control signal in response to irregularities in said electrical signal, said irregularities being representative of excessive deviations in said cross-section or diameter of said yarn, and said discriminator means including at least one correcting circuit means receiving said electrical signal for applying a non-linear characteristic to said electrical signal to provide a corrected signal which emphasizes larger deviations of said cross-section or diameter of said yarn over smaller deviations thereof,   integrator circuit means connected to said correcting circuit means for integrating the corrected signal to determine the frequency of occurrence of said larger deviations of said yarn, and   comparison circuit means connected to said integrator circuit means for comparing the integrated signal with a predetermined reference signal to generate said control signal upon the occurrence of predetermined deviations of said cross-section or diameter of said yarn.     
     
     
       21. An apparatus as claimed in claim 20, wherein said correcting circuit means is connected to the output of said measuring means. 
     
     
       22. An apparatus as claimed in claim 20, wherein said correcting circuit means provides said corrected signal with an at least substantially exponential characteristic. 
     
     
       23. An apparatus as claimed in claim 20, wherein said correcting circuit means are adjustable to vary the non-linear characteristic applied to said electrical signal. 
     
     
       24. An apparatus as claimed in claim 20, wherein said non-linear characteristic of at least two discriminator means is adjustable from a central point. 
     
     
       25. An apparatus as claimed in claim 20, wherein said correcting circuit means includes non-linear elements for providing said non-linear characteristic, and non-linear elements including at least one of a semi-conductor and a variable resistor. 
     
     
       26. An apparatus as claimed in claim 20, wherein the non-linear characteristic of the correcting circuit means is produced by a diode. 
     
     
       27. An apparatus as claimed in clain 20, wherein said correcting circuit means are preceded by an analogue-digital conversion means for producing digital signals corresponding to said electrical signal, said digital signals being processed by said discriminator means. 
     
     
       28. An apparatus as claimed in claim 20, wherein discriminator means further includes at least one frequency-selective filter means connected to said measuring means for determining frequency components of said electrical signal. 
     
     
       29. An apparatus as claimed in claim 28, wherein said frequency-selective filter means include frequency-selective filters connected in series with said correcting circuit means. 
     
     
       30. An apparatus as claimed in claim 29, wherein components of the input signal applied to said integrator circuit means are individually adjustable or weighted, said components being formed by said correcting circuit means and said frequency-selective filter means, the individual adjusting or weighting being selected by the choise of said frequency-selective filters. 
     
     
       31. An apparatus as claimed in claim 28, wherein said frequency-selective filter means includes high-pass and low-pass frequency-selective filters connected in parallel to said correcting circuit means to select only frequencies above the cut-off of said high-pass filter and below the cut-off of said low-pass filter, and suppress all frequencies therebetween. 
     
     
       32. An apparatus as claimed in claim 31, wherein components of the input signal applied to said integrator circuit means are individually adjustable or weighted, said components being formed by said correcting circuit means and said frequency-selective filter means. 
     
     
       33. An apparatus as claimed in claim 20, wherein at least said control signal of the discriminator means is applied to central data-processing facilities for evaluating said irregularities. 
     
     
       34. An arrangement as claimed in claim 20, wherein said predetermined reference signal is provided by the outputs of at least two of said integrator circuit means connected in parallel. 
     
     
       35. An apparatus as claimed in claim 20, wherein said predetermined reference signal is adjustable. 
     
     
       36. An apparatus as claimed in claim 20, further comprising at least one of an acoustic and optical warning system, said warning system being actuated by said control signal. 
     
     
       37. An apparatus as claimed in claim 20, wherein a switch means for turning off the spinning unit is controlled by said control signal. 
     
     
       38. An apparatus as claimed in claim 20, wherein said electrical signal provides a yarn-monitoring signal, said yarn-monitoring signal being applied to a switch means for turning off the spinning unit.